When it comes to shrimp, making healthy, tasty, and ecologically friendly choices can confuse even the most educated consumers. Here's what you really need to know.

You're at your favorite seafood spot listening to the waiter recite the evening's specials, one of which is a delicious-sounding lemongrass shrimp. Your server says the shrimp are from Thailand. But wait: Is he bragging or warning you? You thought you knew about this stuff. Now you're not only hungry but confused too.

That puts you in good company. Americans love shrimp, consuming far more of it than any other seafood—nearly double the amount of tuna we eat a year. But few of us have any idea that almost all of the 1.2 billion pounds of shrimp we eat every year are imported from foreign shrimp farms, many of which have dubious ecological credentials. Perhaps even fewer know that some wild-shrimp fisheries can seriously harm the environment, while others are relatively benign.

The journey these crustaceans take from the ocean to your plate is quite complicated. That's why I decided to explore the compromises that come with wild and farmed shrimp, parsing the bad from the better and the good from the great, so you can dine with a satisfied stomach and a clear conscience.

How to find out what you're eating when you're outIf you're having dinner at a restaurant and you'd like to know the provenance of your prawns, just ask. If your server doesn't know, politely ask if the chef will share that information with you. If the chef can't tell you either, the odds are good you'll be getting foreign farmed shrimp.